Variable-speed driving mechanism



- 1,5193% H, H. HUMMEL I VARIABLE SPEED DRIVING MECHANISM Filed Aug. 24,1922 2 Sheets-Sheet 1 H. H. HUMMEL VARIABLE SPEED DRIVING MECHANISMFiled Aug. 24, 1922 2 Sheets-Sheet 2 Patented 16 1924.

UNITED STATES PATENT OFFICE.

HOWARD H. HUI-MEL, OI BETHLEHEM, PENNSYLVANIA, ASBIGNOR TO BETHLEHEMSTEEL COKPANY, F BETHLEHEM, PENNSYLVANIA, A CORPORATION OF PENNSYL-VANIA.

Application filed au ust 24, 1922.

of the two motors, any desired speed may be imparted to the drivenshaft, from zero to the maximum obtainable.

The object of the invention is to provide mechanism of this character inwhich the connection between each of the driving motors and the drivenshaft includes means for locking the driven shaft against rotationexcept when the motors are energized. in performing certain classes ofwork by 5 means of prior devices of this kind, for instance in rotating9. hoisting drum, a considerable force is exerted continually by, theload in such direction and of S1101 magnitude that the motors will berun backward if by chance thesupply of electricity should beinterrupted. 1n the case of a hoisting drum the failure of the currentsupply might result in serious consequences, the load being allowed tofall unless the drum or other apparatus is provided with automaticbraking devices. In other types of a paratus the effect of the currentfailure mig it be equally disastrous. My invention contemplatesutilization of a connection between each motor and the driven-shaftwhich includes a worm and worm wheel of such type that the motors are atall times locked against movement due to any force imparted to thedriven shaft by the work. Preferw ably I rigidly connect to each gear ofthe differential a worm wheel and to each motor shaft a worm meshin withthe corresponding worm wheel. n the accompan ing drawings a constructionof this type is i lustrated by way of example and is described in detailin the following description.

In the drawings: Fig. 1 is a plan view, partly broken away, of thevariab e speed driving mechanism;

obtained within the maximum capacity of VARIABLE-S?EED DRIVINGMECHANISM.

Serial No. 584,068.

Fig. 2 is a section on line 2-2 of Figure 3; and

Fig. 3 is a section on line 33 of Figure 1.

The driven shaft is indicated at 10 and extends through and is rotatablysupported in suitable bearings 11 in a gear casing rigidly mounted on abase 13. Keyed to the shaft 10 is a spider 14 having differential inionsl5 rotatably mounted thereon. Pin- 10115 15 mesh with differential gears16 and each of these gears is integral with a sleeve 17 rotatablymounted on the driven shaft. Each sleeve 17 has keyed thereto a wormwheel 18 which meshes with a worm 19 fastened on the motor shaft 20. Thetwo. motor shafts 20 are parallel and extend 7 into the casing 12through suitable apertures which constitute bearings, the outer ends ofthe shafts being driven by the armatures of motors 21, which are alsosecured to base 13.

The work which the shaft 10 may accomplish may be varied in characterand may consist either in rotating a hoistin drum, driving a cold saw,or other sue service. In operation either one or both of the motors maybe utilized. These motors may be reversible if desired, and are adaptedto be driven at different speeds. It will be obvious that by varying thes eed of one motor and holding the speed 0 the other constant, differentspeeds may be obtained for the driven shaft 10. and in that both motorsmay be adjusted in this manner, any desired speed of the driven shaftmay be the motors.

Inasmuch as the differential gears are driven from the motors throughworm gearing it will beimpossible, in case the supply of current to themotors should be interrupted, for any force exerted by the work on thedriven shaft 10 to cause rotation of this shaft inasmuch as the wormwheels 18 are frictionally lockedv by the worms with which they enga e.The advanta es of this 100 construction wfil be realized those skilledin the art, and also the possibility of altering the design andarrangement of the component parts of the invention without departingfrom its spirit.

Havin thus described the invention what is claimed as new and desired tobe secured by Letters Patent is:

A unitary. variable-speed power device comprisin a base member, a gearease carried -b tie base member, aligned bearings ear'rie by the gearcase, a shaft extending through the bearings, a sp1der earned by theshaft intermediate the bearings, a plurality of pinions carried by thesp1der, gears loosely mounted on the shaft and engaging opposite sidesof the pinions worm wheels connected to the gears, a pear of o posedbearings in the gear case-in the eentr plane of each worm wheel; shaftsin the bearings, worms carried by the shafts and meshin wlththe wormwheels, and motors carrie by the base member and each having its 15- Intestimony whereof I hereunto affix my 20 signature.

HOWARD H. HUMMEL.

